Economic burden of migraine in Latvia and Lithuania: direct and indirect costs

The search term for identifying systematic reviews on migraine prevalence was as follows. The abstract, title or key word should include the following terms: 1) migraine; 2) prevalence; 3) “systematic review”; or “systematic literature”; or “all existing evidence”. The search was performed on 17 January 2019; only journal articles published in English were retrieved.

Studies were excluded if they used a prevalence estimate from a previous systematic review (n = 3); reviewed studies from a specific region other than Europe (n = 2); focused on patients with chronic migraine only (n = 3); discussed the comorbidities of migraine (n = 15), had other headache, pain or disorder in their focus (n = 5); reviewed aspects of the treatment method (n = 4); or had a completely different focus (n = 10).

Search term for identifying studies on migraine prevalence is Latvia and Lithuania was as follows. The abstract, title or key word should include the following terms: 1) migraine; 2) prevalence; 3) Latvia or Lithuania or Estonia. The search was performed on 22 January 2019; only journal articles published in English were retrieved.

Several studies use data from these surveys for purposes other than estimating migraine-related health care resource utilization (e.g., [26]); these studies are excluded from Table 2.

The estimate of Vo et al. [27] is derived from the data reported in Table 2 in [27]. This estimate includes the number of general/family practitioner visits, neurologist visits psychiatrist visits, ED visits and hospitalizations, and excludes any other health care provider visits. The estimate of Bloudek et al. [28] is derived from the data reported in Table 3 in [28]; the proportion of participants reporting one or more visits was multiplied the mean number of events of those reporting one or more visits. This estimate includes the number of primary care physician visits, neurologist/headache specialist visits, nurse practitioner/physician assistant visits, other specialist visits, emergency room visits and hospitalizations.

The search term defined was as follows: the title and/or the abstract should include migraine, medication and cost, while Latvia or Lithuania might be part of any field, including the text. This search resulted in only one study for Lithuania [20]. As a result, we have also performed an extended search where the title and/or the abstract included migraine, medication and cost without any geographic limitations. The title of the 126 articles identified in this way has been screened; this extended search yielded no additional studies. The search was performed on 5 March 2019; only journal articles published in English were retrieved and screened.

Number of patients with migraine x proportion of patients with chronic migraine x annual cost of therapy with the cheapest triptan = 207.044 x 10.55% x €10.83 = €278,018.

In both countries the number of episodic migraineurs being unemployed were estimated as follows: number of all migraineurs x the proportion of episodic migraineurs x unemployment rate × 1.028, where the proportion of episodic migraineurs was assumed to be 95.12% as reported in Table 3, and the multiplier of 1.028 reflects the higher likelihood of being unemployed if an individual suffers from episodic migraine as reported in [14]. From these unemployed migraineurs only the increment was considered as being unemployed due to their condition (number of all migraineurs x the proportion of episodic migraineurs x unemployment rate × 0.028). The number of chronic migraineurs being unemployed were estimated as follows: number of all migraineurs x the proportion of chronic migraineurs x unemployment rate × 1.19, where the proportion of chronic migraineurs was assumed to be 4.88% as reported in Table 3, and the multiplier of 1.19 reflects the higher likelihood of being unemployed if an individual suffers from chronic migraine as reported in [14]. From these unemployed migraineurs only the increment was considered as being unemployed due to their condition (number of all migraineurs x the proportion of chronic migraineurs x unemployment rate × 0.19). For the remaining migraineurs the primary reason of their unemployment are conditions other than migraine.